If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Q: "Why can't I register with my e-mail address?" or "Why do I get the message that my address is banned when trying to register??"
A: Due to the increase of spammers signing up to the forum I am requiring registration with an email address that isn't from a free email service. Services such as Gmail, Hotmail, Yahoo and the like are not allowed. Users that have signed up with these banned e-mail addresses prior to this enforcement will be allowed. I sincerely apologize for any inconvenience. It is out of necessity that I enforce this rule. Please sign up with an address that was given by your ISP.
Please do not email me asking to make an exception to this rule... Your email will not be read and will automatically be deleted!
** IF YOU SIGN UP FOR THE FORUM YOU WILL BE A NEW USER AND YOUR POSTS MUST BE APPROVED BEFORE APPEARING ON THE FORUM.
IF YOU SPAM THE FORUM--THE POST WILL NEVER BE APPROVED!!

** New users posts are moderated and must be approved because of SPAM **
New users will not be permitted to send PM's or email through the forum!!

2 Visitor Messages

Much of the debate about the difference in tone between the plexi- and aluminium-panel Marshall amps comes from the fact that in 1974 Marshall's US distributor had them change all of the amps sold in the US and Japan over to the much more rugged 6550 instead of the EL34 output tube. This produced a much different sound from the EL34—a sound perceived as less smooth and more metallic when overdriven. This change was brought about due to reliability problems with the EL34's, and the 6550 generally allowed the amps to make it through warranty without problems. The circuit changes required to switch the amps were very minor, and it was easy to change from the 6550 to the EL34 or vice versa by changing a few resistor values, moving the tap for the feedback loop and rebiasing the amp